Systems and methods for deploying a portion of a stent using at least one coiled member

ABSTRACT

The present embodiments provide systems and methods for deploying at least a portion of a stent. In one embodiment, the system comprises a cannula having an outer surface, and at least one coiled member having proximal and distal ends and a plurality of turns disposed therebetween. One of the proximal and distal ends of the coiled member is secured to the outer surface of the cannula, and the other of the proximal and distal ends of the coiled member is unsecured relative to the outer surface of the cannula. A portion of a stent is looped around the unsecured end of the coiled member and disposed within spacing between adjacent turns of the coiled member. Rotation of the cannula subsequently causes the portion of the stent to disengage from the coiled member.

PRIORITY CLAIM

The present patent document is a divisional application that claims thebenefit of priority under 35 U.S.C. § 121 of U.S. patent applicationSer. No. 13/796,395, filed Mar. 12, 2013, which claims the benefit ofpriority of U.S. Provisional Application Ser. No. 61/659,255, filed Jun.13, 2012, and further claims the benefit of priority of U.S. ProvisionalApplication Ser. No. 61/745,181, filed Dec. 21, 2012, all disclosures ofwhich are hereby incorporated by reference in their entirety.

BACKGROUND

The present embodiments relate generally to apparatus and methods fortreating medical conditions, and more specifically, to systems andmethods for deploying a portion of a stent using at least one coiledmember.

Stents may be inserted into an anatomical vessel or duct for variouspurposes. Stents may maintain or restore patency in a formerly blockedor constricted passageway, for example, following a balloon angioplastyprocedure. Other stents may be used for different procedures, forexample, stents placed in or about a graft have been used to hold thegraft in an open configuration to treat an aneurysm. Additionally,stents coupled to one or both ends of a graft may extend proximally ordistally away from the graft to engage a healthy portion of a vesselwall away from a diseased portion of an aneurysm to provide endovasculargraft fixation.

Stents may be either self-expanding or balloon-expandable, or they canhave characteristics of both types of stents. Self-expanding stents maybe delivered to a target site in a compressed configuration andsubsequently expanded by removing a delivery sheath, removing triggerwires and/or releasing diameter reducing ties. With self-expandingstents, the stents expand primarily based on their own expansive forcewithout the need for further mechanical expansion. In a stent made of ashape-memory alloy such as nitinol, the shape-memory alloy may beemployed to cause the stent to return to a predetermined configurationupon removal of the sheath or other device maintaining the stent in itspredeployment configuration.

When trigger wires are used as a deployment control mechanism, thetrigger wires may releasably couple the proximal and/or distal ends of astent or stent-graft to a delivery catheter. Typically, one or moretrigger wires are looped through a portion of the stent near a vertex ofthe stent. For example, trigger wires may be used to restrain a“Z-stent” or Gianturco stent comprising a series of substantiallystraight segments interconnected by a series of bent segments. Thetrigger wires may be disposed through, and pull upon, the bent segmentsto pull the stent closely against the delivery catheter.

Trigger wires also may be used in conjunction with different stentdesigns, such as cannula-cut stents having relatively acute or pointedbends. The designs of cannula-cut stents may facilitate compression ofthe stent to a relatively small delivery profile due to the tight bendsof the apices. With such stents, the trigger wires may be looped aroundone or more vertices formed beneath the proximal and/or distal apices,e.g., a location where an individual apex splits into two separate strutsegments.

If trigger wires are threaded through the vertices of such cannula-cutstents, the trigger wires may become crimped at the vertices duringcompression of the stent to a reduced diameter delivery profile. If thetrigger wires are crimped between the strut segments, the trigger wiresand/or stent segments may become damaged during delivery, particularlyfor nickel-titanium stents that may be sensitive to surfaceimperfections. Furthermore, when compressing a cannula-cut stent havingrelatively acute bends to a significantly reduced radial profile, barbsdisposed near the apices of the stent may become entangled with thestent struts and/or the trigger wires. Still further, in some instance,trigger wires may require a relatively high deployment force when beingretracted, and the provision of multiple trigger wires may add to theprofile of the delivery system.

SUMMARY

The present embodiments provide systems and methods for deploying atleast a portion of a stent. In one embodiment, the system comprises acannula having an outer surface, and at least one coiled member havingproximal and distal ends and a plurality of turns disposed therebetween.One of the proximal and distal ends of the coiled member is secured tothe outer surface of the cannula, and the other of the proximal anddistal ends of the coiled member is unsecured relative to the outersurface of the cannula. A portion of a stent is looped around theunsecured end of the coiled member and disposed within spacing betweenadjacent turns of the coiled member. Rotation of the cannulasubsequently causes the portion of the stent to disengage from thecoiled member.

In one embodiment, the distal end of the coiled member is secured to theouter surface of the cannula and the proximal end of the coiled memberis unsecured relative to the outer surface of the cannula. In thisexample, a portion of the stent is looped around the proximal end of thecoiled member and further is disposed within spacing between adjacentproximal turns of the coiled member in the delivery state.

In an alternative embodiment, the proximal end of the coiled member issecured to the outer surface of the cannula and the distal end of thecoiled member is unsecured relative to the outer surface of the cannula,and a portion of the stent is looped around the distal end of the coiledmember and further is disposed within spacing between adjacent distalturns of the coiled member in the delivery state. In this embodiment, adistal series of turns of the coiled member may be spaced apart furtherfrom one another relative to spacing between a proximal series of turns.Further, a first diameter at the proximal end of the coiled memberpermits attachment to the outer surface of the cannula, while a seconddiameter at the distal end of the coiled member is greater than thefirst diameter and there is a gap disposed between the distal end of thecoiled member and the outer surface of the cannula.

In one embodiment, first and second coiled members are provided and arelongitudinally spaced apart from one another along a length of thecannula. In this example, the first coiled member engages a first stentportion in the delivery state and the second coiled member engages asecond stent portion in the delivery state. The first coiled member maycomprise a greater number of turns that are unsecured relative to thecannula than the second coiled member, thereby enabling the second stentportion to disengage from the second coiled member before the firststent portion disengages from the first coiled member when the cannulais rotated in a uniform direction.

In various embodiments, a ring portion may extend from the stent and isdimensioned to be accommodated within the spacing between adjacent turnsof the coiled member in the delivery state. The ring portion maycomprise a wall thickness that is less than a wall thickness of otherregions of the stent, thereby permitting twisting of the ring portion ina circumferential direction to facilitate coupling of the stent to thecoiled member.

In a further alternative embodiment, at least one suture loop comprisesa proximal region that is coupled to the cannula, and a distal regionthat is retained within one of the plurality of turns of the coiledmember in the delivery state. The suture loop is further coupled arounda portion of a stent in the delivery state. Rotation of the cannulacauses longitudinal movement of the distal region of the suture looprelative to the proximal region of the suture loop, thereby varying theslack in the suture loop and varying expansion of the portion of thestent that is coupled to the suture loop.

Other systems, methods, features and advantages of the invention willbe, or will become, apparent to one with skill in the art uponexamination of the following figures and detailed description. It isintended that all such additional systems, methods, features andadvantages be within the scope of the invention, and be encompassed bythe following claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the followingdrawings and description. The components in the figures are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention. Moreover, in the figures, likereferenced numerals designate corresponding parts throughout thedifferent views.

FIG. 1 is a side view of a first embodiment of an apparatus fordeploying a portion of a stent using at least one coiled member.

FIG. 2 is an enlarged view of the coiled member of FIG. 1.

FIG. 3 depicts an exemplary stent-graft having a portion that may bedeployed using the coiled member of FIGS. 1-2.

FIGS. 4-5 are side views depicting coupling of the stent-graft of FIG. 3to the apparatus of FIGS. 1-2.

FIG. 6 is a perspective view of a proximal apex of a stent that may becoupled to a coiled member.

FIGS. 7-8 are side views depicting twisting of a portion of the proximalapex of the stent of FIG. 6.

FIG. 9 is a perspective view of an alternative proximal apex of a stentthat may be coupled to a coiled member.

FIGS. 10-11 are side views depicting a further alternative proximal apexof a stent that may be coupled to a coiled member.

FIG. 12 is a side view of further alternative proximal apices of a stentthat may be coupled to a coiled member.

FIG. 13 is a side view of yet further alternative proximal apices of astent that may be coupled to a coiled member.

FIG. 14 is a side view of an alternative embodiment of an apparatus fordeploying stent portions using first and second coiled members.

FIG. 15 is a side view depicting coupling of a stent-graft to theapparatus of FIG. 14.

FIG. 16 is a side view of a portion of a stent suitable for use as aninner stent of the stent-graft of FIG. 15.

FIG. 17 is a side view of a portion of an alternative stent suitable foruse as an inner stent of the stent-graft of FIG. 15.

FIG. 18 is a side view of a further alternative embodiment of anapparatus for deploying stent portions using first and second coiledmembers.

FIGS. 19-20 are side views of yet a further alternative embodiment of anapparatus for deploying a portion of a stent using at least one coiledmember in a delivery state and a partially deployed state, respectively.

FIG. 21 is a side view of an embodiment of a protective cage that may beused in conjunction with the coiled member.

FIG. 22 is a side view depicting a portion of a stent used with theapparatus of FIG. 21.

FIGS. 23A-23C are, respectively, cross-sectional views of the protectivecage of FIG. 21 as taken along lines A-A, B-B and C-C.

FIG. 24 is a side-sectional view of the protective cage of FIG. 21.

FIG. 25 is a side view of an alternative protective cage.

FIG. 26 is a side view of a further alternative protective cage.

FIG. 27 is a side view of a stent, shown in a flattened and compressedstate, which is suitable for deployment using a coiled member.

FIG. 28 is a side view of an alternative stent, shown in a flattened andcompressed state, which is suitable for deployment using a coiledmember.

FIG. 29 is a side view of an alternative atraumatic tip and coiledmember arrangement.

FIG. 30 is a side view of a further alternative atraumatic tip andcoiled member arrangement.

FIGS. 31-32 are, respectively, images depicting first and second statesof the coiled member of FIG. 30.

FIGS. 33-35 are, respectively, a side view of a further alternativeatraumatic tip for use with a coiled member arrangement, and end view ofFIG. 33, and a side illustration of the atraumatic tip of FIGS. 33-34with a coiled member disposed in the vicinity.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the present application, the term “proximal” refers to a directionthat is generally closest to the heart during a medical procedure, whilethe term “distal” refers to a direction that is furthest from the heartduring a medical procedure.

Referring to FIGS. 1-2, a first embodiment of an apparatus 20 is shownfor deploying a portion of a stent using at least one coiled member. Theapparatus 20 generally comprises a cannula 30 having an outer surface31, and at least one coiled member 40 having a region that is secured tothe outer surface 31 of the cannula 30.

The cannula 30 may be incorporated as part of a broader stent orstent-graft delivery system, and may span a longitudinal length in whicha distal segment extends outside of a patient's body, and a proximalsegment 34, including the coiled member 40, is delivered towards atarget site inside of a patient's body. The cannula 30 may be used as aninner cannula, to the extent that one or more outer cannulas or sheathsare disposed coaxially over the cannula 30. For example, a stent-graftmay be disposed over an exterior surface of the cannula 30 and withinone or more outer cannulas or sheaths, thereby encompassing thestent-graft during a delivery stage.

The cannula 30 may comprise a tubular member having a lumen sized toallow the cannula 30 to be advanced over a wire guide during delivery. Aproximal region of the cannula 30 may be integrally formed with, orexternally coupled to, an atraumatic tip 35. The atraumatic tip 35 maycomprise proximal and distal regions 36 and 37, respectively, and acentral region 38 disposed therebetween. The proximal and distal regions36 and 37 comprise a smaller outer diameter relative to the centralregion 38, with a first taper allowing for a smooth transition betweenthe proximal region 36 and the central region 38, and a second taperallowing for a smooth transition between the distal region 37 and thecentral region 38.

The coiled member 40 comprises a proximal end 41, a distal end 42, and aplurality of turns 43 disposed therebetween, as shown in FIGS. 1-2. Inthis non-limiting example, the proximal end 41 of the coiled member 40is secured to the outer surface 31 of the cannula 30 using a suitablemechanism, such as a solder, weld, mechanical attachment, friction fit,crimp, or combination of these or other techniques and mechanisms.Accordingly, the proximal end 41 of the coiled member 40 cannot moverelative to the outer surface 31 of the cannula 30. The proximal end 41of the coiled member 40 comprises a first diameter d₁, which may beapproximately the same diameter, or slightly greater than, an outerdiameter of the cannula 30.

The distal end 42 of the coiled member 40 is unsecured relative to theouter surface 31 of the cannula 30, as shown in FIGS. 1-2. The distalend 42 of the coiled member 40 may comprise a second diameter d₂, whichis greater than the first diameter d₁ of the proximal end 41 of thecoiled member 40. There is a separation or gap 44 between the distal end42 of the coiled member 40 and the outer surface 31 of the cannula 30,as best seen in FIG. 2.

The plurality of turns 43 are divided into a proximal series of turns 43a, which have the first diameter d₁, and a distal series of turns 43 b,which have the second diameter d₂. The proximal series of turns 43 a maybe disposed in close proximity or abutting one another, as depicted inFIG. 2. By contrast, the distal series of turns 43 b may be spaced apartfrom one another a greater distance than the proximal series of turns 43a. In FIG. 2, the distal series of turns 43 b are spaced apart apredetermined distance denoted by spacing 45. As will be describedfurther in FIGS. 4-5 below, a portion of a stent 60 may be coupled to atleast one of the distal series of turns 43 b, and secured within thespacing 45 between adjacent distal turns.

The exemplary coiled member 40 may be formed from stainless steel,nitinol, titanium, or other suitable biocompatible materials. Ifmanufactured from nitinol, the unsecured end of the coiled member may beheat-set so that it contracts around the outer surface 31 of the cannula30 when disposed within the body, thereby reducing the likelihood of thecoiled member 40 snagging the stent 60 or other components. In oneexample, the coiled member 40 is formed from a material that hasradiopaque properties.

Referring now to FIG. 3, an exemplary stent-graft 50, having aproximally-located stent 60 coupled to a graft material 90, may bedeployed in a controlled manner using the coiled member 40 of FIGS. 1-2,as shown further in the exemplary coupling sequence of FIGS. 4-5 below.In this non-limiting embodiment, the stent 60 may be manufactured from acontinuous cylinder into which a pattern may be cut by a laser or bychemical etching to produce slits in the wall of the cylinder. Theresulting structure may then be heat set to give it a desired finalconfiguration. As shown in FIG. 3, the final configuration may include ashape having a series of proximal apices and a series of distal apices.A proximal end 62 of the stent 60 may comprise multiple adjacentproximal apices 62 a and 62 b, while a distal end 64 of the stent 60 maycomprise multiple adjacent distal apices 64 a and 64 b, as shown in FIG.3.

In FIG. 3, at least one pair of adjacent, proximal apices 62 a and 62 bmay comprise different features. For example, as shown in FIG. 3, afirst proximal apex 62 a may comprise an end region 70 having a bore 71formed therein, wherein the bore 71 is configured to receive a sutureloop 65, as explained further below. A second, adjacent proximal apex 62b may comprise an end region 75 having an integral barb 77 formedtherein, as shown in FIG. 3. The barb 77 may be formed by laser cuttinga desired barb shape into the end regions 75. A slit 76 therefore isformed into each end region 75 after the desired barb shape is formed,as shown in FIG. 3. Once the desired barb shape is cut, a main body ofthe barb 77 may be bent in a radially outward direction with respect tothe end region 75. The angle may comprise any acute angle, oralternatively may be substantially orthogonal or obtuse. If desired, thebarb 77 may be sharpened, for example, by grinding the tip of the barb,to facilitate engagement at a target tissue site.

Referring still to FIG. 3, the stent 60 may comprise at least one strutsegment disposed between the proximal and distal apices. For example,multiple angled strut segments may be disposed between a first proximalapex 62 a and a corresponding distal apex 64 a, and an identical set ofangled strut segments may be disposed between an adjacent, secondproximal apex 62 b and a corresponding distal apex 64 b. By way ofexample, a first proximal apex 62 a extends distally and splits intofirst and second angled strut segments 67 and 68, respectively, therebyforming a proximal vertex 78, as shown in FIG. 3. In a compressed state,the first and second angled strut segments 67 and 68 may be compressedsuch that they are substantially parallel to one another. Similarly,each distal apex 64 a and 64 b may extend in a proximal direction andsplit into the first and second angled strut segments 67 and 68,respectively, thereby forming a distal vertex 79. A first angled strutsegments 67 may meet with an adjacent second angled strut segment 68,thereby forming a transition region 80. In this manner, the stent 60 maybe formed into a continuous, generally cylindrical shape, as shown inFIG. 3.

Expansion of the stent 60 is at least partly provided by the angledstrut segments 67 and 68, which may be substantially parallel to oneanother in a compressed state, but may to tend to bow outward away fromone another in the expanded state shown in FIG. 3. The stent 60 may beformed from any suitable material, such as a laser-cut nitinol cannula.If manufactured from nitinol, the stent 60 may be inclined to assume theexpanded state shown in FIG. 3 upon removal of a delivery sheath orengagement with the coiled member 40, as explained in FIGS. 4-5 below.

Each transition region 80 may comprise a larger surface area relative tothe angled segments, since the transition regions are composedsubstantially of multiple different angled segments 67 and 68. The stent60 may comprise at least one barb 82 disposed in at least one of thetransition regions 80. The barb 82 may be formed integrally, as part ofthe strut, or may comprise an external barb that is adhered to a surfaceof the transition regions 80. As shown in FIG. 3, multiple integralbarbs 82 are provided. Like the barbs 77 noted above, the barbs 82 maybe formed by laser cutting a desired barb shape into the transitionregions 80. A slit 81 therefore is formed into the transition region 80after the desired barb shape is formed, as shown in FIG. 3. Since thetransition regions 80 may comprise an increased surface area relative toother regions of the stent 60, it may be easier to perforate portions ofthe transition regions 80 without adversely affecting the structuralintegrity of the stent. Once the desired barb shape is cut, a main bodyof the barb 82 may be bent in an outward direction at any angle withrespect to the transition region 80 and optionally may be sharpened tofacilitate engagement at a target tissue site.

Each of the distal apices 64 a and 64 b may comprise an end region 88having a bore 89 formed therein, as shown in FIG. 3. The distal end 64of the stent 60 may be coupled to a proximal end 92 of the graftmaterial 90. The distal apices 64 a and 64 b may be coupled to the graftmaterial, for example, using one or more sutures that are looped throughthe graft material and the bores 89 of the stent 80. In this manner, thestent 60 may be used as an attachment stent for endovascular graftfixation. For example, the graft material 90 may overlap with ananeurysm to seal off fluid flow into the aneurysm, while the proximalend 62 of the stent 60 may extend in a proximal direction away from thegraft material, e.g., to engage a healthy portion of a vessel wall awayfrom a diseased portion of the aneurysm. As will be apparent, one ormore additional stents may be coupled to an inner or outer surface ofthe graft material 90, i.e., at a location distal to the stent 60, tohelp maintain patency throughout the graft material. While multipleexemplary zig-zag stents 95 are shown coupled to the graft material 90between the proximal and distal ends 92 and 94 of the graft material 90in FIGS. 4-5, it will be apparent than any shape of stent may be used,and such stents may be coupled to either the inner or outer surfaces ofthe graft material 90.

The stent 60 has a reduced diameter delivery state so that it may beadvanced to a target location within a vessel or duct. The stent 60 alsohas an expanded deployed state to apply a radially outward force upon atleast a portion of a vessel or duct, e.g., to maintain patency within apassageway, or to hold open the lumen of a graft. In the expanded state,fluid flow is allowed through a central lumen of the stent 60. Further,the struts of the stent 60 may comprise a substantially flat wireprofile or may comprise a rounded profile. As best seen in FIG. 3, thestruts of the stent 60 generally comprise a flat wire profile.

The stent 60 may be manufactured from a super-elastic material. Solelyby way of example, the super-elastic material may comprise ashape-memory alloy, such as a nickel titanium alloy (nitinol). If thestent 60 comprises a self-expanding material such as nitinol, the stentmay be heat-set into the desired expanded state, whereby the stent 60can assume a relaxed configuration in which it assumes the preconfiguredfirst expanded inner diameter upon application of a certain cold or hotmedium. Alternatively, the stent 60 may be made from other metals andalloys that allow the stent 60 to return to its original, expandedconfiguration upon deployment, without inducing a permanent strain onthe material due to compression. Solely by way of example, the stent 60may comprise other materials such as stainless steel, cobalt-chromealloys, amorphous metals, tantalum, platinum, gold and titanium. Thestent 60 also may be made from non-metallic materials, such asthermoplastics and other polymers.

While one exemplary stent 60 is shown in FIG. 3 and described in FIGS.4-5 below, various alternative stent configurations may be used inconjunction with the coiled member 40 of FIGS, 1-2. Moreover, the stentmay be deployed alone, or as part of a stent-graft system, as depictedherein.

Referring now to FIGS. 4-5, an exemplary coupling of the stent-graft 50of FIG. 3 to the deployment apparatus of FIGS. 1-2 is shown anddescribed. The stent-graft 50 has an uncoupled state in which thestent-graft 50 is positioned coaxially over the cannula 30 with theproximal end 62 of the stent 60 in longitudinal proximity relative tothe distal end 42 of the coiled member 40, as shown in FIG. 4. Duringassembly, the suture loops 65 that are coupled to the proximal apices 62a of the stent 60 are threaded around the distal end 42 of the coiledmember 40 one at a time, preferably until all of the suture loops 65 arecoupled to the coiled member 40. Such coupling may be achieved byrotating the cannula 30 in a clockwise direction until the proximal end62 of the stent 60 is sufficiently compressed in a radially inwarddirection, as depicted in FIG. 5. It should be noted that the gap 44between the distal end 42 of the coiled member 40 and the outer surface31 of the cannula 30 permits positioning of the suture loops 65 aroundthe distal series of turns 43 b.

The suture loops 65 are further accommodated within the spacing 45between the distal series of turns 43 b. The suture loops 65 preferablyare coupled to the coiled member 40 in a manner in which at least onesuture loop 65 is positioned around at least one full turn of the distalseries of turns 43 b, and preferably around at least 1.5 turns at thedistal end 42 of the coiled member 40, thereby reducing the likelihoodof inadvertent uncoupling of the suture loops 65 from the coiled member40.

The coupling shown in FIG. 5 secures the stent 60 to the cannula 30 viathe coiled member 40 in a manner that may subsequently facilitateinsertion of the subassembly comprising the cannula 30 and thestent-graft 50 into an outer sheath. As will be apparent, the outersheath is configured to radially restrain other regions of thestent-graft 50 for delivery to a target site within a patient's anatomy.

In this embodiment, the suture loops 65 are coupled to every otherproximal apex 62 a to restrain the stent 60 during delivery. The sutureloops 65 are not coupled to the second proximal apices 62 b, whichcomprise the barbs 77. By restraining the alternating proximal apices 62a using the suture loops 65 coupled to the coiled member 40, theadjacent second proximal apices 62 b also may be indirectly pulled in aradially inward direction during delivery. The configuration of thestent 60, and in particular the angled segments 67 and 68 that meet upat transition regions 80, facilitates the indirect compression of theadjacent second proximal apices 62 b. Since only selected ones of theproximal apices are restrained during delivery, the number of sutureloops 65 may be reduced. Moreover, since the barbs 77 are only disposedon every other apex, barb entanglement may be reduced or eliminated.

An introducer, similar to that described in PCT application WO98/53761,entitled “A Prosthesis and a Method and Means of Deploying aProsthesis,” which is incorporated herein by reference in its entirety,may be used to deploy the stent-graft 50. PCT application WO98/53761describes a deployment system for an endoluminal prosthesis whereby theprosthesis is radially compressed onto a delivery catheter and iscovered by an outer sheath. To deploy the system, the operator slides orretracts the outer sheath over the delivery catheter, thereby exposingthe prosthesis. The prosthesis expands outwardly upon removal of thesheath. The operator can directly manipulate the sheath and the deliverycatheter, which provides the operator with a relatively high degree ofcontrol during the procedure. However, in the current embodiments,trigger wires and any of their associated sleeves would not be necessaryto deploy the stent-graft 50. Rather, the cannulas 30, 130, 130′ and 230and the coiled members 40, 140 and 180 of the present embodiments may beincorporated as part of the deployment system with the stent-graft 50being positioned coaxially between the cannula 30 and the outer sheath.A mechanism, such as a pin vise, may be employed to prevent inadvertentrotation of the cannula 30 prior to the intended rotation as describedin the present application.

In the present embodiments, a wire guide may be advanced to the targetsite, and the cannula 30 may be advanced over the wire guide to positionthe apparatus 20 at the desired location in proximity to the targetsite, with the atraumatic tip 35 reducing the likelihood of injury tobodily passageways during delivery. The outer sheath is disposed overthe cannula 30 and the stent-graft 50 during insertion to the targetsite. Upon proper positioning at the target site using a desired imagingmodality, the outer sheath is then retracted to expose at least aportion of the stent 60.

When the stent 60 is at least partially exposed, and it is desirable todeploy the proximal end 62 of the stent 60, the cannula 30 may berotated in a counter-clockwise direction until the suture loops 65 areuncoupled from the coiled member 40, i.e., in a reverse manner fromwhich the suture loops 65 were coupled to the coiled member 40. Thestent 60 then may be deployed as shown in FIG. 4, and the remainder ofthe stent-graft 50 may be deployed by further retraction of the outersheath or actuation of any other devices that are radially constrainingthe remainder of the stent-graft 50. As will be explained further inFIGS. 14-15 below, a plurality of coiled members may be used toselectively deploy multiple stent portions of the stent-graft 60.

Advantageously, the proximal end 62 of the stent 60 is radiallyrestrained without the use of convention trigger wires that span a fulllongitudinal length of the delivery system. Accordingly, the radialprofile of the delivery system may be reduced without the provision ofmultiple trigger wires and one or more associated sleeves to house thetrigger wires, thereby reducing packing density of the system. Moreover,deployment may be simplified as reduced deployment forces are expectedto be needed relative to the use of conventional trigger wires.

As a further advantage, deployment of the stent 50 using the apparatus20 comprising at least one coiled member 40 may allow for more precisepositioning of the stent 50. In particular, deployment using the coiledmember 40 may provide a more controlled unwinding of the associatedportion of the stent 50, whereas the release of conventional triggerwires may require higher deployment forces that can cause a portion ofthe stent to jump longitudinally, thereby potentially deploying thestent offset from the intended target site.

Referring now to FIGS. 6-8, a portion of an alternative stent 60′ isdescribed for use with the apparatus 20 comprising at least one coiledmember 40 as described in FIGS. 1-2 and FIGS. 4-5. The alternative stent60′ is similar to the stent 60 of FIG. 3, with a main exception that analternative proximal end 62′ comprises at least one alternative proximalapex 62 b′ having an region comprising an eyelet 72.

The eyelet 72 may be formed within a ring portion 73 that is disposed atthe proximal end of a proximal extension segment 74. The proximalextension segment 74 extends in a proximal direction away from the endregion 75 having the integral barb 77, as shown in FIGS. 6-8.

In accordance with one aspect, the ring portion 73 and the proximalextension segment 74 comprise a wall thickness that is less than a wallthickness of the end region 75 having the integral barb 77, as best seenin FIG. 6. Advantageously, the reduced wall thickness of the ringportion 73 and the proximal extension segment 74 allows at least thering portion 73 to twist in a circumferential direction to facilitateloading of the proximal apex 62′ around the coiled member 40. In theexample shown, the ring portion 73 twists in a circumferential directionabout 90 degrees between a first state shown in FIG. 7 and a secondstate shown in FIG. 8. As will be apparent, the ring portion 73 maytwist greater or less than 90 degrees, and the exemplary depictionbetween the states of FIGS. 7 and 8 is not intended to be limiting.Moreover, at least a portion of the proximal extension segment 74 maytwist in the circumferential direction. The proximal extension segment74 may twist a greater amount proximally since it is further fromattachment from the end region 75 having the greater wall thickness.

As another advantage, the proximal extension segment 74 provideslongitudinal separation of the ring portion 73 housing the eyelet 72from the end region 75 having the integral barb 77. Accordingly, whenthe eyelet 72 is threaded around the coiled member 40, the proximalextension segment 74 provides a longitudinal spacing that reduces thelikelihood of entanglement between the coiled member 40 and the integralbarb 77 of the end region 75.

In the example of FIGS. 6-8, the ring portion 73 and the proximalextension segment 74 may be integrally formed with the end region 75. Ifthe stent 60′ is formed from nitinol or a similar material, thesuperelastic properties of such material can facilitate circumferentialtwisting of the ring portion 73 between the first and second statesshown in FIGS. 7 and 8.

The alternative proximal apex 62 b′ shown in FIGS. 6-8 may be providedon each and every proximal apex of the stent 60′. Alternatively, thealternative proximal apex 62 b′ may be provided on fewer than all of theproximal apices of the stent 60′, and the remaining proximal apices maybe provided with only barbs, e.g., as depicted by the proximal apices 62b in FIG. 3 above, or the proximal apices may comprise other features.

Referring now to FIG. 9, a further alternative stent 60″ has a proximalend 62″ having at least one proximal apex 62 b″, which is similar to theproximal apex 62 b′ of FIGS. 6-8, with a main exception that analternative ring portion 73′ having an eyelet 72′ and proximal extensionsegment 74′ are formed separately from the end region 75. In thisexample, a bore 83 is formed at a proximal edge of the end region 75 ata location spaced proximally away from the integral barb 77, as shown inFIG. 9. A distal portion 84 of the proximal extension segment 74′ issized to be received within the bore 83 of the end region 75. The distalportion 84 of the proximal extension segment 74′ then may be secured,e.g., using a solder or weld, within the bore 83 of the end region 75,forming the proximal apex 62 b″ shown in FIG. 9. In this alternativeembodiment, the ring portion 73′ and the proximal extension segment 74′optionally may be formed of a different material, such as a moreflexible material, relative to the remainder of the stent 60″.

Referring now to FIGS. 10-11, a further alternative stent 60′″′ has aproximal end 62′″ having at least one proximal apex 62 b′″. In thisexample, a wire loop 54 is coupled to the end region 75 having theintegral barb 77 by winding the wire loop 54 around a portion of theslit 76 formed into the end region 75. The wire loop 54 may be woundsecurely by placing a first loop portion 55 under the end region 75,then around the barb 77, and folding over proximally through the slot76, as shown in FIG, 10. Then, a second loop portion 56, whichpreferably is larger than the first loop portion 55 and disposedprimarily proximally to the first loop portion 55, may be pulled in aproximal direction as depicted in FIG. 11. By pulling the second loopportion 56 proximally, the first loop portion 55 shortens and tightensaround the end region 75, as shown in FIG. 11. Optionally, a solder maybe applied to hold the first loop portion 55 tightly around the endregion 75. The resulting structure comprises the second loop portion 56extending proximally away from the end region 75 in a manner such thatthe second loop portion 56 can be wound around the coiled member 40 ofFIGS. 1-2 and 4-5, in the manner generally described above with respectto the suture loop 65.

Advantageously, the wire loop 54 may be formed from a flexible material.If formed from nitinol or a similar material, the superelasticproperties of such material can facilitate circumferential twisting ofthe second loop portion 56 between the first and second states shown inFIGS. 7 and 8, thereby facilitating engagement around the coiled member40. Moreover, the wire loop 54 may be considerably thinner than the endregion 75 to facilitate engagement around the coiled member 40, e.g., bypermitting twisting of the second loop portion 56 as needed duringloading, and also by having a reduced thickness wire loop that caneasily fit within the gap 44 and spacing 45 around the coiled member 40,as explained above.

Referring now to FIGS. 12-13, further alternative proximal ends ofexemplary stents, suitable for deployment via the apparatus 20 havingthe coiled member 40, are shown and described. In FIG. 12, analternative proximal region of a stent comprises alternating proximalapices 62 a′ and 62 b, The proximal apices 62 b are substantiallyidentical to the proximal apices 62 b described above in FIG. 3.However, the proximal apices 62 a′ differ from the proximal apices 62 aof FIG. 3 by replacing the end region 70 having the bore 71 that isconfigured to receive the suture loop 65 with an alternative end region70″ that has an integral eyelet 72″ within a ring portion 73″. In theembodiment of FIG. 12, the ring portion 73″ may be disposed at theproximal end of the end region 70″. The ring portion 73″ then may be cutinto this pattern in a manner integral with the remainder of the stent,e.g., by laser cutting a cannula. The ring portion 73″ subsequently maybe bent radially inward at a desired angle, such as between 45 and 90degrees, and then heat-set into the bent position to facilitateengagement with the coiled member 40 described above.

The alternative embodiment of FIG. 13 is similar to FIG. 12, with theexception that alternative proximal apices 62 a″ comprise end regions70′″ having ring portions 73′″ that house eyelets 72′″ that arepositioned further distally, i.e., spaced apart from proximal end of theend regions 70′″. As will be apparent, the eyelet positioning may bemodified without departing from the spirit of the present embodiments.Moreover, in certain embodiments, the ring portions housing the eyeletmay be disposed further proximally than shown in FIG. 12 such that thering portions extend proximally beyond then end of the adjacent proximalapices 62 b.

Referring now to FIGS. 14-15, an alternative apparatus 120 is shown fordeploying a plurality of stent portions using a plurality of coiledmembers. The apparatus 120 is similar to the apparatus of 20 of FIGS.1-2 and FIGS. 4-5, with main exceptions noted below. In particular, theapparatus 120 of FIGS. 14-15 comprises a first coiled member 140 and asecond coiled member 180, which are coupled to an outer surface 131 of acannula 130 at locations that are longitudinally spaced apart from oneanother.

The first coiled member 140 comprises a proximal end 141, a distal end142, and a plurality of turns 143 disposed therebetween. In thisembodiment, the distal end 142 of the first coiled member 140 is securedto the outer surface 131 of the cannula 130 using a suitable mechanism,such as a solder, weld, mechanical attachment, friction fit, crimp, orcombination of these or other techniques and mechanisms, as generallydescribed above. The proximal end 141 of the first coiled member 140 isunsecured relative to the outer surface 131 of the cannula 130 at alocation just proximal to an atraumatic tip 135, as shown in FIG. 14.The proximal end 141 of the first coiled member 140 preferably comprisesthe second diameter d₂, shown in FIG. 2 above, and provides the sameseparation or gap 44 described in FIG. 2 above between the proximal end141 of the first coiled member 140 and the outer surface 131 of thecannula 130.

Similarly, the second coiled member 180 comprises a proximal end 181, adistal end 182, and a plurality of turns 183 disposed therebetween. Thedistal end 182 of the second coiled member 180 is secured to the outersurface 131 of the cannula 130, as generally described above, at alocation distally spaced apart from the first coiled member 140, asshown in FIGS. 14-15. The proximal end 181 of the second coiled member180 is unsecured relative to the outer surface 131 of the cannula 130,as shown in FIG. 14. The proximal end 181 of the second coiled member180 preferably comprises the second diameter d₂ and provides the sameseparation or gap 44 between the proximal end 181 of the second coiledmember 180 and the outer surface 131 of the cannula 130.

During delivery, the first coiled member 140 is coupled to a firstportion of the stent-graft 50′, while the second coiled member 180 iscoupled to a second portion of the stent-graft 50′. In this example, thefirst coiled member 140 is coupled to the suture loops 65 that arecoupled to the proximal apices 62 a of the stent 60, as explained inFIGS. 3-5 above, while the second coiled member 180 is coupled to acentral region of the graft material 90. In particular, at least oneinner stent 195 is coupled to an inner surface of the graft material 90and configured to engage the coiled member 180, in the manner generallydescribed above with respect to FIGS. 1-5. It should be noted that whilethe second coiled member 180 and a portion of the cannula 130 isdisposed within the graft material 90 in FIG. 15, for illustrativepurposes these components are shown in solid, not dashed, lines.Advantageously, the first and second coiled members 140 and 180 mayradially restrain different, spaced-apart sections of the stent-graft50′ during deployment.

Moreover, in the example of FIGS. 14-15, the first coiled member 140 hasa greater number of proximal turns 143 a that are spaced apart furtherrelative to distal turns 143 b to accommodate a portion of thestent-graft 50′, relative to the number of proximal turns 183 a that arespaced apart further relative to distal turns 183 b on the second coiledmember 180. Accordingly, by varying the number of proximallyspaced-apart turns 143 a and 183 a on the first and second coiledmembers 140 and 180, respectively, one portion of the stent-graft 50′may be disengaged from its respective coiled member 140 or 180 beforethe other portion of the stent-graft 50′. In this example of FIGS.14-15, since the second coiled member 180 has fewer proximal turns 183 athat are spaced apart to accommodate the stent 195, then the stent 195will disengage from the proximal turns 183 a relatively fast to deploythe central portion of the stent-graft 50′ shortly after the cannula 130is rotated. Subsequently, as the cannula 130 is rotated further, thesuture loops 65 coupled to the proximal apices 62 a of the stent 60 willdisengage from the greater number of proximal turns 143 a of the firstcoiled member 140 to deploy the proximal stent 60, after the centralportion of the stent-graft 50 has been deployed.

As will be appreciated, any number of coiled members may be providedalong the length of the cannula to selectively control deployment of anynumber of corresponding regions along a stent or stent-graft. By varyingthe number of spaced-apart turns, different portions of the stent orstent-graft may be selectively deployed before other portions simply bycontinuing to rotate a single cannula comprising the multiple coiledmembers.

Moreover, the portions of the stent-graft 50′ that are coupled to thefirst and second coiled members 140 and 180 may be at least partiallyopened and closed to allow for a degree of repositioning before finaldeployment. For example, rotating the cannula 130 in a first directionmay cause the portions of the stent-graft 50′ to expand at leastpartially radially outward, while rotation in the opposing direction maycause the portions of the stent-graft 50′ to contract radially inward,and this may be repeated any number of times before final deployment.

If the coiled members are unsecured relative to the cannula at theirproximal ends, as depicted in FIGS. 14-15, then the cannula may berotated in the opposite direction to achieve deployment, as compared tothe coiled member 40 of FIGS. 1-2 that is unsecured at its distal end.In any of the embodiments herein, the cannula may comprise one or morecoiled members that are unsecured at their proximal ends or unsecured attheir distal ends, or combinations thereof in which at least one coiledmember is unsecured proximally and at least one coiled member isunsecured distally.

Referring to FIGS. 16-17, examples of stents that are suitable for useas the inner stent 195 of FIG. 15, which may be coupled to the secondcoiled member 180, are shown and described. In FIG. 16, a stent 195 acomprise a zig-zag shape comprising first and second generally straightsegments 191 and 192 that are angled relative to one another andseparated by a plurality of apices 193. An eyelet 194 may be coupled toone of the apices 193, as shown in FIG. 16, or any other suitablesegment of the stent 195 a. In use, the unsecured, spaced-apart proximalturns 183 a of the second coiled member 180 are disposed through theeyelet 194 of the stent 195 a, thereby securing the stent 195 a to thesecond coiled member 180.

In FIG. 17, a stent 195 b comprises a cannula-cut structure having firstand second cells 196 a and 196 b, which are separated by a spacing. Apartial circumferential slit 197 is formed in the spacing to create aring member 198, and a bore 199 then is formed within the ring member198, as depicted in FIG. 17. The ring member 198 having the bore 199then may be bent radially inward at a desired angle, such as between 45and 90 degrees, and then heat-set into the bent position, as generallydescribed with respect to the ring member 73″ and 73′″ of FIGS. 12-13,to facilitate engagement with the second coiled member 180.

Referring to FIG. 18, an alternative apparatus 120′ is shown fordeploying a plurality of stent portions using a plurality of coiledmembers, and is similar to the apparatus 120 of FIGS. 14-15, with mainexceptions noted below. In particular, an alternative cannula 130′ ofthe apparatus 120′ comprises a plurality of tapers 165 and 166 thatincrease in diameter from distal to proximal directions. The largestdiameters of the tapers 165 and 166 generally match the second diametersd₂, explained above in FIG. 2, of the first and second coiled members140 and 180, respectively. Accordingly, the proximal ends of the tapers165 and 166 are substantially flush with the outer diameters d₂ of thefirst and second coiled members 140 and 180. In this embodiment, thedistal ends 142 and 182 of the first and second coiled members 140 and180 may be secured to the proximal ends of the tapers 165 and 166,respectively, e.g., using a solder or other suitable technique, therebyeliminating the provision of the smaller turns of the first and secondcoiled members 140 and 180.

Referring now to FIGS. 19-20, a further alternative apparatus 220 isshown for deploying a portion of a stent 260 using a coiled member 240.In FIGS. 19-20, a cannula 230, which is similar to the cannula 30described above, comprises an outer surface 231, an atraumatic tip 235,and a wire guide lumen 239. The coiled member 240 comprises proximal anddistal ends 241 and 242, respectively, and a plurality of turns 243disposed therebetween. The distal end 242 of the coiled member 240 issecured to the outer surface 231 of the cannula 230, e.g., using solderor weld 249, while the proximal end 241 of the coiled member 240 isunsecured relative to the outer surface 231 of the cannula 230, asdepicted in FIGS. 19-20.

The apparatus 220 further comprises a swivel 270 coupled to the cannula230 at a location proximal to the coiled member 240, and a plurality ofsuture loops 275 a and 275 b. Each of the suture loops 275 a and 275 bcomprises a proximal region 276 that is coupled to the swivel 270, e.g.,by being disposed through a bore 271 in the swivel 270, and furthercomprises a distal region 277 that is retained in a delivery statebeneath one of the plurality of turns 243 of the coiled member 240, asdepicted in FIGS. 19-20. The stent 260 comprises a first proximal apex262 a that is coupled to the suture loop 275 a, and further comprises asecond proximal apex 262 b that is coupled to the suture loop 275 b. Thesuture loops 275 a and 275 are disposed around portions of the first andsecond proximal apices 262 a and 262 b, respectively, in a manner thatrestrains the first and second proximal apices 262 a and 262 b in thedelivery state of FIG. 19.

The first and second proximal apices 262 a and 262 b of the stent 260are movable between a first configuration of FIG. 19 in which they arerestrained radially inward, a second configuration of FIG. 20 in whichthey are at least partially deployed radially outward, and a finalconfiguration in which they are fully deployed. In the firstconfiguration of FIG. 19, the distal regions 277 of the suture loops 275a and 275 b are positioned beneath the plurality of turns 243 at alocation distally away from the swivel 270, thereby maintaining thesuture loops 275 a and 275 b in a state of relative tension in which thesuture loops 275 a and 275 b are generally parallel to the cannula 230,which holds the first and second proximal apices 262 a and 262 b in aradially restrained state. In the second configuration of FIG. 20, thecannula 230 may be rotated in a direction that causes the distal regions277 of the suture loops 275 a and 275 b to move closer to the swivel270, thereby providing slack for the suture loops 275 a and 275 b andallowing the first and second proximal apices 262 a and 262 b to be atleast partially deployed radially outward based on their resilientnature.

Advantageously, if a physician does not wish to ultimately deploy thefirst and second proximal apices 262 a and 262 b when in the partiallydeployed state of FIG. 20, the physician may then rotate the cannula 230in an opposing direction that causes the suture loops 275 a and 275 b toresume a state of relative tension to move the first and second proximalapices 262 a and 262 b radially inward to the state of FIG. 19, therebyallowing for repositioning of the first and second proximal apices 262 aany number of times after partial deployment. Therefore, the embodimentof FIGS. 19-20 provides a degree of reversibility prior to finaldeployment. Ultimately, a physician can deploy the first and secondproximal apices 262 a and 262 b at the desired location by rotating thecannula 230 to cause the distal regions 277 of the suture loops 275 aand 275 b to pass proximally beyond the proximal end 241 of the coiledmember 240. The suture loops 275 a and 275 b are then free fromengagement with the first and second proximal apices 262 a and 262 b,and the cannula 230 may be removed from the patient's body with thesuture loops 275 a and 275 b still coupled to the swivel 270.

Optionally, if circumferential orientation of the stent 260 isimportant, then to permit better circumferential positioning at theproximal end of the stent 260, a single trigger wire or other means maybe used to temporarily lock the swivel 270 in place circumferentially asthe stent 260 is positioned within the body. In this example, the singletrigger wire or other means can be disengaged from the swivel 270, e.g.,by being withdrawn from one of the bores 271 of the swivel 270, uponproper orientation within the body when the stent 260 is still in thedelivery state, to thereby permit subsequent rotation of the swivel 270and allowing unwinding of the suture loops 275 a and 275 b from thecoiled member 240 as the cannula 230 is rotated.

Referring now to FIGS. 21-24, an apparatus 320 is shown for deploying aportion of a stent 360 using at least one coiled member 140, andcomprises a protective cage 370 for enclosing the coiled member 140. Inthis example, the exemplary coiled member 140 is the same coiled memberthat is secured to the outer surface 131 of the cannula 130, asexplained above in FIG. 14, though it is contemplated that theprotective cage 370 may be used in conjunction with other coiledmembers, including those alternative coiled members shown herein.

The protective cage 370 comprises a first end 371 having an outerdiameter dc₁, and a second end 372 having a second outer diameter dc₂,as best seen in FIGS. 21 and 24. In the embodiment of FIGS. 21-24, wherethe exemplary coiled member 140 is secured to the cannula 130 at itsdistal end and unsecured at its proximal end, then the first end 371having the first outer diameter dc₁ will be the proximal end of theprotective cage 370, while the second end 372 having the second outerdiameter dc₂ will be the distal end of the protective cage 370. It isnoted that the diameter at the first or proximal end 371 of theprotective cage 370 can be larger to accommodate the greater diameter ofthe coil at its unsecured proximal end that is spaced apart relative tothe cannula 130, as depicted by separation or gap 44 in FIG. 2 above. Atthe second or distal end 372 of the protective cage 370, the reducedsecond outer diameter dc₂ may be provided because the diameter of thecoiled member 140 is reduced for coupling to the cannula 130. Further,the second or distal end 372 of the protective cage 370 may bepositioned distally of the coiled member 140, as shown in FIG. 21, andthe second outer diameter dc₂ may be slightly larger than the outersurface 131 of the cannula 130. It should be noted that a taper 374reduces the diameter of the protective cage 370 between the first endhaving the outer diameter dc₁ and the second end having the reducedouter diameter dc₂.

It should be noted that, if the unsecured end of the coiled member islocated distally instead of proximally, then the axial orientation ofthe protective cage 370 may be reversed. For example, if the coiledmember 40 of FIGS. 1-2 and 4-5 is used, which is unsecured at its distalend, then the protective cage 370 may have the first end 371 of greaterdiameter located distally, while the second end 372 of lesser diameteris located proximally, thereby generally corresponding to the shape ofthe coiled member.

In the embodiment of FIGS. 21-24, the protective cage 370 furthercomprises a plurality of struts 375 separated by a plurality of slots376. In this non-limiting example, four struts 375 a-375 d are depictedas being separated by four slots 376 a-376 d, as depicted among thevarious FIGS. 21-22, 23A-23C and 24. However, any number of slots andstruts may be provided. Moreover, the number of slots may corresponddirectly to the number of proximal apices 361 of the stent 360 that needto be restrained, as generally depicted in FIG. 22 and explained below,or there may be variability between the number of slots and the numberof proximal apices of the stent 360.

Each of the struts 375 a-375 d and slots 376 a-376 d have proximal anddistal ends, and are generally parallel to each other in a directionrunning along a longitudinal axis of the apparatus, as shown in FIG. 21.Each of the slots 376 a-376 d has a width that is greater than a widthof the proximal apices 361 of the stent 360, thereby allowing portion ofthe proximal apices 361 to extend through an associated slot, asdepicted in FIG. 22. Each of the slots 376 a-376 d may accommodate oneproximal apex 361, or multiple proximal apices.

In one embodiment, the protective cage 370 is designed to cooperate withat least a portion of an atraumatic tip 335. In FIGS. 21-24, theatraumatic tip 335 may comprise proximal and distal regions 336 and 337,respectively, and a central region 338 disposed therebetween. Theproximal and distal regions 336 and 337 comprise a smaller outerdiameter relative to the central region 338, with a first taper allowingfor a smooth transition between the proximal region 336 and the centralregion 338, and a second taper allowing for a smooth transition betweenthe distal region 337 and the central region 338. The proximal region336 may comprise a similar shape to the proximal region 36 of theatraumatic tip 35 of FIG. 1 and FIGS. 4-5.

The distal region 337 of the atraumatic tip 335 may comprise an outersurface that corresponds to the shape of an inner surface at a proximalregion of the protective cage 370. In particular, the protective cage370 comprises a proximal inner taper 381, as shown in FIG. 24. The outersurface of the distal region 337 of the atraumatic tip 335 generallyannularly abuts the proximal inner taper 381 in an assembled state.

In accordance with one aspect, the protective cage 370 can rotatecircumferentially relative to the atraumatic tip 335 and the cannula130. Notably, the proximal inner taper 381 of the protective cage 370 isdisposed around the distal region 337 of the atraumatic tip 335, whilethe distal end 372 of the protective cage 370 is disposed around theouter surface 131 of the cannula 130. Since the proximal and distalregions of the protective cage 370 are not secured to the atraumatic tip335 and the cannula 130, respectively, the protective cage 370 canrotate circumferentially relative to these adjacent components.

A distal stop member 379 may be positioned adjacent to the distal end372 of the protective cage 370, as shown in FIG. 21. The distal stopmember 379 allows the protective cage 370 to rotate relative to thecannula 130, but prevents the protective cage 370 from sliding distallyover the cannula 130. The distal stop member 379 may be formedintegrally with the cannula 130, or as an external component secured tothe outer surface 131 of the cannula, and may comprise any suitablebiocompatible material.

The proximal inner taper 381 of the protective cage 370 extends inwardto an opening 382, shown in FIG. 24, which has a diameter that allowspassage of the cannula 130 so that the cannula 130 can be coupled to theatraumatic tip 335. Moreover, a stepped surface 383 is provided justdistal to the opening 382, as shown in FIG. 24. The stepped surface 383may be generally perpendicular to the longitudinal axis of the cannula130. The stepped surface 383 prevents the proximal apices 361 of thestent 360 from sliding off of the coiled member 140 prematurely, and mayreduce the possibility that the proximal apices 361 of the stent 360become inadvertently lodged under the struts 375 a-375 d. Preferably,the proximal end 141 of the coiled member 140 is disposed immediatelyadjacent to the stepped surface 383, as depicted in FIG. 21, therebyfurther reducing the possibility of inadvertent uncoupling of theproximal apices 361 of the stent 360 from the coiled member 140 prior todesired rotation of the cannula 130.

The protective cage 370 further comprises a main housing 384, which isdisposed between the stepped surface 383 and the distal end 372, asshown in FIG. 24. The main housing 384 is sized for housing the coiledmember 140 therein, and has an inner diameter that remains larger thanthe coiled member along its longitudinal length, thereby permittingrotation of the coiled member 140 within the main housing 384.

The protective cage 370 may be formed from stainless steel, nitinol,polymers, or other suitable biocompatible materials. Moreover, theprotective cage 370 may be manufactured as a single component, ormultiple components that are secured together. In one embodiment, theprotective cage 370 may be manufactured by forming an outer shell ofmaterial, and then inserting material that forms the proximal innertaper 381 and the stepped surface 383, and separately cutting the slots376 a-376 d into the outer shell.

In the non-limiting example of FIG. 22, the stent 360 comprises a seriesof proximal apices 361 and a series of distal apices 363. Each of theproximal and distal apices 361 and 363 are separated by a plurality ofstrut segments 365 and 366, which enable radial expansion from thecompressed state shown in FIG. 22 to a generally cylindrical expandedstate similar to the stent 60 depicted in FIG. 4. The distal apices 363may be coupled to graft material 90 using sutures threaded through oneor more bores 364 formed in the distal apices 363 that overlap with thegraft material, as shown in FIG. 22.

The manner of using the apparatus 320 is similar to use of the priorapparatuses 20 and 120, explained above. However, in the embodiment ofFIGS. 21-24, the proximal apices 361 of the stent 360 are coupled to thecoiled member through the slots 376 a-376 d. For example, a firstproximal apex 361a may be positioned over the slot 376 a, as depicted inFIG. 22, and the proximal end 141 of the coiled member 140 may bealigned with a coupling member 362 of the first proximal apex 361a. Thecoupling member 362 of FIG. 22 may be in the form of the suture loop 65,the wire loop 54, or any one of the eyelets 72, 72′, 72″, 72′″ describedabove, or another suitable connector coupled to the proximal apex 361a,which can be coupled or looped around the proximal end 141 of the coiledmember 140. The proximal apex 361a may be pushed radially inward andheld steady, while the cannula 130 and the coiled member 140 are rotatedin a first direction, thereby allowing the coupling member 362 of theproximal apex 361a to be wound in a proximal to distal directionsecurely about the coiled member 140. Subsequently, a second proximalapex 361b may be positioned over the slot 376 b and the same processachieved to couple the second proximal apex 361 b about the coiledmember 140, and this process may be repeated until all of the proximalapices 361 of the stent 360 are coupled to the coiled member 140,through the slots 376 a-376 d, as shown in FIG. 22. As noted above,there may be a one-to-one ratio of proximal apices 361 of the stent 360to slots in the protective cage 370, or alternatively, multiple proximalapices 361 of the stent 360 may be coupled to the coiled member 140through the same slot in the protective cage 370,

After all of the proximal apices 361 of the stent 360 are coupled to thecoiled member 140 through the slots 376 a-376 d of the protectivemember, a physician may deploy the stent 360 in the same manner as theexplained in FIGS. 4-5 above. In particular, upon proper positioning atthe target site using a desired imaging modality, an outer sheath isretracted to expose at least a portion of the stent 360. When the stent360 is at least partially exposed, and it is desirable to deploy theproximal end of the stent 360, the cannula 130 may be rotated in acounter-clockwise direction until the coupling member 362 of the firstproximal apex 361a is uncoupled from the coiled member 140, i.e., in areverse manner from which these connectors were coupled to the coiledmember 140. The stent 360 then may be deployed as shown in FIG. 4 above,and the remainder of the stent-graft may be deployed by furtherretraction of the outer sheath or actuation of any other devices thatare radially constraining the remainder of the stent-graft.

Advantageously, during deployment of the stent 360 using the protectivecage 370, the protective cage 370 can rotate circumferentially relativeto the atraumatic tip 335 and the cannula 130. This allows theorientation of the protective cage 370 and the stent apices 361 toremain generally the same while the cannula 130 and the coiled member140 are rotated circumferentially during deployment.

As a further advantage, the protective cage 370 encloses the coiledmember 140 and reduces the possibility that the coiled member 140 caninterfere with, damage, or snag various endovascular, stent or graftstructures during manipulation and removal of the delivery device. Theprotective cage 370 also may reduce the likelihood of apices of thestent 360 becoming caught on the coiled member 140 by providing a guidedrelease for the apices.

As noted above, if the unsecured end of the coiled member is locateddistally instead of proximally, then the axial orientation of theprotective cage 370 may be reversed. Moreover, if multiple coiledmembers are used, e.g., as in the embodiment of FIGS. 14-15, thenmultiple protective cages 370 may be provided that each enclose adifferent coiled member.

Referring now to FIG. 25, an alternative protective cage 370′ is similarto the protective cage 370 of FIGS. 21-24, with like reference numbersrepresenting like parts, except as noted below. In this example, anenclosing member 390 that surrounds the distal end 142 of the coiledmember 140 that is secured to the outer surface 131 of the cannula 130.The enclosing member 390 may comprise a first end 391 that is spacedapart from the cannula 130 to accommodate a portion of the coiled member140, a second end 392 that is secured to the outer surface 131 of thecannula 130, and a tapered region 394 that bridges the differentdiameters of the first and second ends 391 and 392, as depicted in FIG.25. The alternative protective cage 370′ may comprise a longitudinalregion 374′, as shown in FIGS. 25, which comprises an intermediate outerdiameter dc₃, which has a dimension less than the first end 371 havingthe outer diameter dc₁ and greater than the second end 372 having theouter diameter dc₂ , depicted in the earlier embodiment of FIG. 24. Thelongitudinal region 374′ further has an inner diameter that is slightlylarger than an outer diameter at the first end 391 of the enclosingmember 390. Advantageously, the enclosing member 390 provides a barrierbetween a portion of the coiled member 140 and the protective cage 370′,which may reduce potential drawbacks arising from direct interferencebetween the distal end 142 of the coiled member 140 and the protectivecage 370′.

Referring now to FIG. 26, an alternative protective cage 370″ is similarto the protective cages 370 and 370′ above, with a main exception that aplurality of slots 376′ has proximal regions 377 that are wider thandistal regions 378. The widening of proximal regions 377 of the slots376′ may yield an easier time coupling the stent 360 to the coiledmember 140 during loading, and may facilitate release of the stent 360from the coiled member 140 given less potential interference from theproximal region 377 of the slots 376′. The proximal apices 361 of thestent 360 can also be modified, e.g., with widened proximal tips, sothat they only side out of the protective cage 370″ at the proximalregion 377 of the slots 376′.

Referring now to FIGS. 27-28, two different stent designs are shown,which are alternatives to the stents 60 and 360 described above. In FIG.27, a stent 360′, which is shown in a flattened and compressed state,comprises a series of proximal apices 361′ and a series of distal apices363′. Each of the proximal and distal apices 361′ and 363′ are separatedby a plurality of strut segments 365′ and 366′, which enable radialexpansion from the compressed state shown in FIG. 27 to a generallycylindrical expanded state similar to the stent 60 depicted in FIG. 4.

Each of the proximal apices 361′ comprises the coupling member 362, asexplained with respect to FIG. 22 above, and further comprises anintegral barb 367. Each of the distal apices 363′ comprises a suturebore 364′, an imaging marker 368, and an integral barb 369. The suturebore 364′ overlaps with graft material 90, as depicted in FIG. 22, andallows suturing of a portion of each distal apex 363′ to the graftmaterial 90. The imaging marker 368, which is disposed proximal to thesuture bore 364′, may be aligned precisely with the proximal edge of thegraft material 90 to enable precise placement of the proximal edge underan imaging modality.

The stent 360′ may comprise any number 361n′ of proximal apices 361′,where “n” is the number of apices. In the example of FIG. 27, “n” isequal to twelve, and each of the twelve proximal apices 361a′ through361n′ have identical characteristics, including axial lengths. A firstproximal apex 361a′ is loaded onto the coiled member 40 or 140 in themanner described above via engagement with the coupling member 362, andeach subsequent proximal apex 361 is secured to the coiled member 40 or140 until the final proximal apex 361n′ is secured to the coiled member.It should be noted that each of the proximal apices 361a′ through 361n′comprises a region having a relatively thin strut segment 388, having anotched region 389 formed therein, which advantageously may permit thisregion of the proximal apex to rotate or bend to facilitate coupling tothe coiled member 40 or 140, in the manner described above for theproximal extension segment 74 of FIGS. 6-8.

Referring now to FIG. 28, an alternative stent 360″ is identical to thestent 360′ of FIG. 27, with the exception that alternative proximalapices 361″ comprise different axial lengths relative to one another. Inthe example of FIG. 28, each of the alternative proximal apices 361″comprises a progressively larger axial length, such that a firstproximal apex 361a″ comprises the smallest axial length, while the lastproximal apex 361n″ comprises the greatest axial length. Axial lengthsof relatively thin strut segments 388′ and their associated notchedregions 389′ may be varied to achieve the length differential betweenadjacent proximal apices 361a″ through 361n″, which yields a staggeredaxial positioning of the coupling members 362 of each apex, as shown inFIG. 28. The first proximal apex 361a″ is loaded onto the coiled member40 or 140 in the manner described above via engagement with the couplingmember 362, and each subsequent proximal apex 361 is secured to thecoiled member 40 or 140 until the final proximal apex 361n″ is securedto the coiled member.

The axial length differential between coupling members 362 of adjacentproximal apices 361a″ through 361n″ can be determined according to theformula i=p/n, where “i” is the axial length between coupling members362 of adjacent proximal apices 361a″ through 361n″, “p” is the pitch ofthe coiled member, and “n” is the number of proximal apices. Forexample, where there are twelve proximal apices 361a″ through 361n″, thevalue of “i” may equal 0.167 mm where the pitch of the coiled member is2.0 mm, i.e., i=p/n corresponds to 0.167 mm=2.0 mm/12.

Advantageously, by modifying the axial length between adjacent proximalapices 361a″ through 361n″, and yielding the staggered axial positioningof the coupling members 362 of each apex, capture of the couplingmembers 362 may be facilitated during securement to the coiled members40 and 140. Further, the coupling members 362 can endure lower strainssince the first proximal apex 361a″ does not have to bend more toaccommodate other points during the loading process. The proximal apices361a″ through 361n″ can therefore be positioned in a uniform radiallyabout the coiled member 40 or 140.

Referring now to FIG. 29, an alternative atraumatic tip 435 comprisesproximal and distal regions 436 and 437, respectively, and a centralregion 438 disposed therebetween. The proximal and distal regions 436and 437 comprise smaller outer diameters relative to the central region438, with a first taper allowing for a smooth transition between theproximal region 436 and the central region 438, and a second taperallowing for a smooth transition between the distal region 437 and thecentral region 438. In this example, a distal taper 439 is formed at anangle α relative to the central region 438 and also to the mainlongitudinal axis of the device. The angle α preferably is minimized toachieve a minimal distance for threading the coupling members 362 of thestents on and off the coiled members 40 and 140. Additionally, in thisexample, a length of a distal face 449 of the atraumatic tip 439 may begreater than the second outer diameter d₂ of the coiled member 140, asillustrated previously. By having the second outer diameter d₂ of thecoiled member 140 be less than the length of the distal face 449 of theatraumatic tip 439, the chances of inadvertent snagging of the proximalend 141 of the coiled member 140 may be reduced.

Further, a distance x between the proximal end 141 of the coiled member140 and the distal end of the atraumatic tip 435 may be optimized sothat the distance x is just slightly larger than an axial lengthnecessary for coupling the coupling members 362 of the stents on and offthe coiled members 40 and 140. By minimizing the distance x, thelikelihood of the coupling members 362 of the stents becominginadvertently disengaged from the coiled members 40 and 140 is reduced.Further, by minimizing the distance x, the likelihood of the coiledmember 140 snagging on another part of the delivery system or a bodilystructure may be reduced.

Referring now to FIGS. 30-32, an alternative atraumatic tip 435′ issimilar to the atraumatic tip 435 of FIG. 29, but comprises analternative distal region 437′ having a notched region 440 formed in thedistal face of the atraumatic tip 435′. The notched region to 440generally follows at least a portion of the profile of the coiled member140, as shown in FIG. 30. Further, the distance x between the proximalend 141 of the coiled member and the distal end of the atraumatic tip435, as explained in FIG, 29, may be maintained in the embodiment ofFIGS. 30-32, although in an angled manner that corresponds to theangular profile of the coiled member 140, as best seen in FIG. 30.

In this example, the notched region 440 follows the contours of alongitudinal notch 441 and angled segments 442 and 443, whichcollectively allow for the separation distance x between the coiledmember 140 and the atraumatic tip 435′ to be maintained while theproximal end 141 of the coiled member 140 at least partially axiallyoverlaps with the atraumatic tip 435′. A first state of the deliverysystem is shown in FIGS. 30 and 31, in which the proximal end 141 of thecoiled member 140 at least partially axially overlaps with theatraumatic tip 435′, may be used during delivery into, and removal from,a patient's vascular system. A second state of the delivery system isshown in FIG. 32, in which the proximal end 141 of the coiled member 140has been rotated to be disposed distal to the atraumatic tip, may occurduring deployment as the stent-graft is held longitudinally steady. Inone further embodiment, the atraumatic tip 435′ may be longitudinallymovable relative to the coiled member 140, such that when deployment ofthe stent-graft is completed, the atraumatic tip 435′ may be advanceddistally relative to the coiled member 140 until the proximal end 141 ofthe coiled member is at least partially seated within the notched region440 of the atraumatic tip 435′ for subsequent removal from thevasculature.

In the embodiment of FIGS. 30-32, multiple advantages are achieved.First, the likelihood of the coupling members 362 of the stents becominginadvertently disengaged from the coiled member 140 is reduced. Further,since the proximal end 141 of the coiled member 140 at least partiallyaxially overlaps with the atraumatic tip 435′, the likelihood of thecoiled member 140 snagging on another part of the delivery system or abodily structure may be significantly reduced.

Referring now to FIGS. 33-35, a further alternative atraumatic tip 435″is similar to the atraumatic tips 435 and 435′ of FIGS. 29-32, butcomprises an alternative distal region 437″ having a notched region440″, and an alternative central region 438″ having a channel 450. It isnoted that the coiled member 140 is omitted in FIG. 33 for clarity, butis shown in FIG. 35.

The notched region 440″ may comprise tapered wall portions 441 and 442,which taper in an angled manner radially inward to a valley 443. Thevalley 443 has proximal and distal ends 443 a and 443 b, respectively,as depicted in FIG. 35. The proximal end 443 a of the valley 443 maytransition into the channel 450 of the central region 438″ of theatraumatic tip 435″. The channel 450 may be used as a conduit fordelivering flushing fluid, which may be provided in a distal to proximaldirection through the valley 443 and subsequently through the channel450.

The distal end 443 b of the valley 443 is disposed in close longitudinalproximity, and preferably slightly proximal to, the proximal end 141 ofthe coiled member 140. The distance between the proximal end 141 of thecoiled member 140 and the distal end of the atraumatic tip 435″ remainssuch that there is sufficient space for the coupling members 362 ofstents to be released from the coiled member 140, as described above.Further, the proximal end 141 of the coiled member 140 may terminate ata circumferential location slightly offset from the center of the valley443. For example, in FIG. 35, the proximal end 141 of the coiled member140 is shown slightly above the center of the valley 443, and about evenwith the tapered wall portion 441. In this manner, the center of thevalley 443 will be aligned precisely with the coupling members 362 asthey exit from engagement with the proximal end 141 of the coiled member140.

In the embodiment of FIGS. 33-35, multiple advantages are achieved. Asone example, the valley 443 may significantly reduce the likelihood ofthe atraumatic tip 435″ becoming caught on a radially deployed couplingmember 362. In particular, after deployment of the stent, the deliverysystem including the atraumatic tip 435″ will be retracted distallyoutside of the patient, and during the phase of initial retraction, thevalley 443 helps provide a ramp-like feature to ensure that the deployedcoupling member 362 of the stents will not become caught on theatraumatic tip 435″ upon its removal.

The valley 443 of the notched region 440″ also provides a ramp-likepathway for the coupling members 362 to follow as they move radiallyoutward from the proximal end 141 of the coiled member 140 towards avessel wall. Accordingly, the provision of the valley 443 maysignificantly reduce the likelihood of the coupling members 362 of thestents becoming caught on the atraumatic tip 435″ during deployment, inaddition to after deployment.

While various embodiments of the invention have been described, theinvention is not to be restricted except in light of the attached claimsand their equivalents. Moreover, the advantages described herein are notnecessarily the only advantages of the invention and it is notnecessarily expected that every embodiment of the invention will achieveall of the advantages described.

We claim:
 1. A method for deploying at least a portion of a stent, themethod comprising: introducing a cannula having an outer surface, andfurther introducing at least one coiled member having proximal anddistal ends, wherein one of the proximal and distal ends of the coiledmember is secured to the outer surface of the cannula, and the other ofthe proximal and distal ends of the coiled member is unsecured relativeto the outer surface of the cannula; introducing a stent, wherein aportion of the stent is disposed around the end of the coiled memberthat is unsecured relative to the outer surface of the cannula; androtating the cannula to cause the coiled member to rotate and therebydisengage the portion of the stent from the coiled member, wherein firstand second coiled members are longitudinally spaced apart from oneanother along a length of the cannula, the method comprising rotatingthe cannula to cause a first stent portion to disengage from the firstcoiled member and rotating the cannula to cause a second stent portionto disengage from the second coiled member.
 2. The method of claim 1,where the first coiled member has a plurality of turns and the portionof the stent that is disposed around the unsecured end of the firstcoiled member is disposed within a spacing between adjacent turns of thefirst coiled member.
 3. The method of claim 2, where the proximal end ofthe first coiled member is secured to the outer surface of the cannula,and the distal end of the first coiled member is unsecured relative tothe outer surface of the cannula, such that the stent is looped aroundthe distal end of the first coiled member and further is disposed withina spacing between adjacent distal turns of the first coiled member in adelivery state.
 4. The method of claim 1, where the distal end of thefirst coiled member is secured to the outer surface of the cannula, andthe proximal end of the first coiled member is unsecured relative to theouter surface of the cannula, such that the stent is looped around theproximal end of the first coiled member and further is disposed within aspacing between adjacent proximal turns of the first coiled member in adelivery state.
 5. The method of claim 1, where the first coiled memberand the second coiled member each comprise a plurality of turns, and thefirst coiled member comprises a greater number of turns that areunsecured relative to the cannula than the second coiled member, therebyenabling the second stent portion to disengage from the second coiledmember before the first stent portion disengages from the first coiledmember when the cannula is rotated in a uniform direction.
 6. A methodfor deploying at least a portion of a stent, the method comprising:introducing a cannula having an outer surface, and further introducingat least one coiled member having proximal and distal ends, wherein oneof the proximal and distal ends of the coiled member is secured to theouter surface of the cannula, and the other of the proximal and distalends of the coiled member is unsecured relative to the outer surface ofthe cannula; introducing a stent in a position being disposed over thecannula, wherein a portion of the stent is disposed around the end ofthe coiled member that is unsecured relative to the outer surface of thecannula; and rotating the cannula to cause the coiled member to rotateand thereby disengage the portion of the stent from the coiled member.7. The method of claim 6, where the coiled member has a plurality ofturns and the portion of the stent that is disposed around the unsecuredend of the coiled member is disposed within a spacing between adjacentturns of the coiled member.
 8. The method of claim 6, where the proximalend of the coiled member is secured to the outer surface of the cannula,and the distal end of the coiled member is unsecured relative to theouter surface of the cannula, such that the stent is looped around thedistal end of the coiled member and further is disposed within a spacingbetween adjacent distal turns of the coiled member in a delivery state.9. The method of claim 6, where the distal end of the coiled member issecured to the outer surface of the cannula, and the proximal end of thecoiled member is unsecured relative to the outer surface of the cannula,such that the stent is looped around the proximal end of the coiledmember and further is disposed within a spacing between adjacentproximal turns of the coiled member in a delivery state.
 10. The methodof claim 6, wherein first and second coiled members are longitudinallyspaced apart from one another along a length of the cannula, the methodcomprising rotating the cannula to cause a first stent portion todisengage from the first coiled member and rotating the cannula to causea second stent portion to disengage from the second coiled member. 11.The method of claim 10, where the first coiled member and the secondcoiled member each comprise a plurality of turns, and the first coiledmember comprises a greater number of turns that are unsecured relativeto the cannula than the second coiled member, thereby enabling thesecond stent portion to disengage from the second coiled member beforethe first stent portion disengages from the first coiled member when thecannula is rotated in a uniform direction.
 12. A method for deploying atleast a portion of a stent, the method comprising: introducing a cannulahaving an outer surface, and further introducing at least one coiledmember having proximal and distal ends, wherein one of the proximal anddistal ends of the coiled member is secured to the outer surface of thecannula, and the other of the proximal and distal ends of the coiledmember is unsecured relative to the outer surface of the cannula;introducing a stent, wherein a portion of the stent is disposed aroundthe end of the coiled member that is unsecured relative to the outersurface of the cannula; rotating the cannula to cause the coiled memberto rotate and thereby disengage the portion of the stent from the coiledmember; and using a protective cage to encircle at least a portion ofthe coiled member while the portion of the stent is disengaged from thecoiled member.
 13. The method of claim 12, where the protective cagecomprises a plurality of struts separated by a plurality of slots, wherea portion of the stent that is releasably secured to the coiled memberextends through one of the plurality of slots in a delivery state. 14.The method of claim 13, where at least one of the plurality of slots hasproximal and distal regions and a width at the proximal region isgreater than a width at the distal regions.
 15. The method of claim 13,where each of the plurality of struts and each of the plurality of slotsare generally parallel to each other in a direction running along alongitudinal axis of the apparatus.
 16. The method of claim 12, wherethe protective cage is circumferentially rotatable relative to thecannula.
 17. The method of claim 12, where an atraumatic tip is coupledto the cannula, the method further comprising disposing at least aportion of the atraumatic tip beneath the protective cage, and whereprotective cage can rotate circumferentially relative to the atraumatictip and the cannula.